1. Field of the Invention
The present invention relates to minerals used for animal nutrition. More particularly, it relates to a method of converting lipoproteins and transition metal salts to transition metal amino acid chelates and fats; and also the products made by the method. The method comprises: the base hydrolysis of the lipoproteins to sodium or potassium salts of alpha amino acids mixed with fatty acids; neutralization of the salts to acids; and reaction of the alpha amino acids with soluble salts of the transition metals to form chelates mixed with fatty acids.
2. Description of Related Art
The transition metals have been recognized for many years as important trace minerals for maintaining health and good nutrition in animals. The Official Publication, 1996, Association of American Feed Control Officials (AAFCO) recognizes and defines such products as item "57.142 Metal Amino Acid Chelate. The Product resulting from the reaction of a metal ion from a soluble metal salt with amino acids with a mole ratio of one mole of metal to one to three (preferably two) moles of amino acid to form coordinate covalent bonds. The total molecular weight of the hydrolyzed chelate must not exceed 800."
In U.S. Pat. No. 5,698,724, Anderson et al disclose a method of preparing a metal amino acid complex from protein starting material by strong acid hydrolysis of protein to provide an amino acid hydrolyzate in about 1 to 3 hours at elevated temperature and pressure. Metal oxide is then added to the amino acid hydrolyzate to form a metal amino acid complex. Anderson et al use a strong inorganic acid at the high concentration of 6 normal, which is then neutralized to a pH of 4 to 5 by addition of alkali or alkaline earth hydroxide.
U.S. Pat. Nos. 3,925,433, Abdel-Monem et al; 3,941,818, Abdel-Monem; 3,950,372, Abdel-Monem; 4,021,569, Abdel-Monem; and 4,067,994, Anderson et al teach preparation of 1:1 complexes of alpha amino acids, preferably methionine, and transition metals. These complexes are 1:1 complex salts prepared from pure amino acids. The foregoing patents refer to complexes and not to chelates. Complexes are not necessarily chelates, but chelates are considered to be special ring structured metal complexes.
Ned L. Jensen in U.S. Pat. No. 3,969,540 taught a method of preparing metal proteinates consisting of metal chelates of polypeptides using enzymatic hydrolysis so that the chelates are substantially free from metal salts and from single amino acid proteinates.
None of the foregoing references provide for the base hydrolysis of lipoproteins into an aqueous mixture of sodium or potassium salts of alpha amino acids and fatty acids, followed by the reaction of the aqueous mixture with transition metal salts to form a palatable mixture of transition metal amino acid chelates mixed with fatty acids.
Many of the proteinacious materials economically available as by-products or wastes are lipoproteins containing substantial amounts of fats or lipid groups conjugated with protein groups into long chain polymers. These lipoproteins are resistant to hydrolysis by enzymatic or acid hydrolysis. Further, the lipids when treated with strong acids, such as sulfuric acid, at elevated temperatures char, making the resultant product unpalatable to animals.
In this disclosure "lipoprotein" means lipids, or fats, or fatty acid groups conjugated with protein and, or amino acid groups into polymeric structures. Lipoproteins are found in most animal generated proteins, including, single cell proteins, fermentation solids, and biological process by-products where microbes are cultivated to produce a particular chemical such as lysine or other amino acids.
Transition metals have varying degrees of chelate forming stability with chelating agents, and the stabilities of the metals vary with any given chelating agent. When the term "transition metals" is used herein it means zinc, copper, manganese, iron, cobalt, copper and magnesium, as a group or as individual metals.
The term "biosynthesis" is used herein to mean the synthesis of desired chemical compounds by the use of particular strains of microbes which have the ability to convert raw materials, such as ammonia, sugar, and water by catalytic action to products such as alpha amino acids. The biosyntheses always leaves a by-product of fractured cell walls from the dead microbes on completion of the process.
The term "conventional means of drying" herein means drying a product by ordinary drying methods in use commercially, such as by fluid bed, rotary drum, steam tube, spray, or tray dryer.
Bioavailability of the transition metals is defined as the portion of the metal which is absorbed, transported to its site of action, and converted to a physiologically active form--the availability of the metal for use by the consuming animal.
It is a primary object of this invention to provide a method of preparing amino acid transition metal chelates as a palatable bioavailable source of transition metals for animal nutrition from lipoproteins and transition metal salts.
It is another object of this invention to provide a method of preparing these chelates from biological and agricultural industry by-products such as solids recovered from fermentation processes, solid single cell feed proteins from biosynthesis from hydrocarbons or alcohols, solids recovered from biosynthesis of organic chemicals and from blood meal, fish meal and other meals of animal origin.
It is still another object to produce a palatable bioavailable transition-metal amino acid chelate-fatty acid composition for animal nutrition.